The present application is directed to surgical screwdrivers for inserting a fastener into a patient and, more particularly, to screwdrivers and methods of use that control the amount of torque that can be applied to a fastener.
Various surgical procedures utilize one or more fasteners that are attached within the patient. The fasteners include a shaft that is inserted into a support member such as an implant, bone, or tissue. The fastener further includes a head positioned at an end of the shaft that includes a receiver for engagement with a screwdriver. The shaft may include threads to assist in inserting the screw into the support member and in preventing the screw from backing out of the support member. The head may include a variety of different receivers with different shapes and sizes depending upon the context of use.
The screwdriver includes a tip that engages the receiver and a shaft to rotate the fastener and drive it into the support member. The screwdriver may further include a handle that is grasped and rotated by the surgeon to insert the fastener into the support member.
One potential problem with previous screwdrivers is the amount of torque that is applied to the fastener. In some instances, the fastener could shear if excessive torque is applied through the screwdriver. The shear often occurs in the fastener between the connection of the head and the shaft. Further, fasteners may be constructed of a polymeric material that is relatively weak compared to the strength of metal. These fasteners are particularly prone to shear when exposed to an excessive amount of torque.